<html>
<head>
<script type="text/javascript">
function run() {
  document.documentElement.offsetLeft;
  var leg = document.getElementById('leg');
  leg.style.marginLeft = '100px';
} 
</script>
</head>
<body onload="run();">
<fieldset>
  <legend id="leg">Legend</legend>
  fieldset contents
</fieldset>
</body>
</html>
